Engine-cooling fan



Mal'. 27, 1923. 1,449,685. C. LUTHER ET AL.

ENGINE COOLING FAN.v

FILED `F`E1s,18,1.f122. 2 SHEETS-s115211.

Mar. 2'7, 1923.

c. LUTHER 5T AL.

ENGlNE COOLING FAN 2 SHE s-SHEET 2.

FILED FEB. 18| |922.

Patented Mar. 27, 1923.

UNITED STATES CARL LUTHER AND HENRY MOELLER, OF ICOUNCIL BLUFFS, IOWA.

ENGINE-COOLING FAN.

Application filed February 18, 1922. Serial No. 537,536.

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Be it known that we, CARL LUTHER and HENRY MOELLER, citizens of theUnited States, residing at Council Bluffs, in the county ofPottawattamie and State of Iowa,

have invented certain new and useful Improvements in Engine-CoolingFans, of which the following is a specification, reference being hadtherein to the accompanyingr drawings.

The invention relates to cooling fans for internal combustion engines,and has for its object to provide a device of this character wherein thepitch of the fan blades automatically changes to their maximum pitchwhen the engine is running slowly, and to their minimum upon high speedof the engine. It has been found, especially in slow running engines, asfor instance, tractor en,.-l

gines, that the engine heats on low speed and that on high speed themovement of the tractor or vehicle in combination with the coolingaction of the fau is sufficient to cool the engine, which is not truewhere the engine is running slowly, at which time a maximum pitch of thefan blades will have 'the maximum cooling action on the engine. Afurther object is tov provide a cooling fan for engines comprising a hubmember having a plurality of radially disposed chambers therein havingspirally arranged ribs, which engage spirally arranged grooves in discscarried by -the fan blades arms, which extend into the chambers throughad- A justable bushings and coiled springs interposed between the discsand the bushings and adapted to be compressed by the discs incident tothe centrifugal force of the fan blades during the rotation of the hub.The

spiral ribs and grooves forming means whereby the fan blades will bemoved and the pitch thereof reduced during the high speed of the engine.

A further object is to provide circumfer' ential adjustment of the fanblades on the xfan arms, thereby allowing the pitch of the fan blades tobe varied, and accurately adjusted.

lVith the above and other objects in view the invention resides in thecombination and arrangement of parts as hereinafter set forth, shown inthe drawings, described and claimed, it being understood that changes inthe precise embodiment of the invention may be made within' the scope ofwhat is claimed without departing from the spirit of the invention.

In the drawings Figure l is a front elevation of the fan.

Figure 2 is a top plan view. Figure 3 is a horizontal, sectional viewthrough the hub of the fan.

Figure 4 is a vertical sectional View through the hub of the fan.

Figure 5 is a vertical transverse sectional View taken on line 5 5 ofFigure 4.

Figure 6 is a detail sectional view through one of the fan blades takenon line 6-6 of Figure 1. v

Referring to the drawings, the numeral l designates the hub of the fan,which hub is rotatably mounted on a supporting shaft 2, which isthreaded at 3 into a support 4. which support may be a portion of theengine. Extending rearwardly from the hub l is a drive pulley 5, whichis adapted to be belted to the crank shaft of the engine or to any otherportion thereof in the usual manner. It has been found that internalcombustion engines, particularly those used in connection with tractorsand farm implements when running slowly rapidly become heated and thatthe maximum cooling action is desired at this time, rather than when anengine is running fast, consequently being cooled to a greater degree bythe movement of the vehicle and the rapid rotation of the fan. To obtaina maximum cooling action of the fan when the engine is running slowly,it is obvious that the fan blade 6 -must be at a maximum pitch. Howevera maximum pitch, for instance forty-five degrees would not be adesirable pitch when the engine is operated at high speed on account ofthe strain on the fan belt and the power required to operate the fan. Toaccomplish the above result the fan blade arms 7 extend into radiallydisposed chambers S of the hub 1 of the fan and Y -outer ends ofthechambers 8. It will be seen that by adjustinor the bushings 13 inwardlyor outwardly iat the tension of the springs l2 may be varied. As the fanrothe springs 12 prevent outward movement of the discs 9, and as theblades 6 are set at their maximum pitch, for instance at fortyvedegrees, it will be seen that a maximum cooling action will be obtainedon the engine, however as the engine increases in speed the centrifugalforce will overcome the expansive action of the coiled springs 12,thereby causing the an arms 7 to moveI outwardly and during theiroutward movement the spiral ribs 11 will cause the discs 9 to partiallyrotate thereby reducing the pitch of the fan blades 6 and consequentlyrequiring less power to operate the Jfan, at the same time securingsufficient cooling action for cooling the engine.

Each blade 6 has secured thereto by means of rivets 14 a sleeve 15,which sleeve is provided with an arcuate slot 16, through which the setscrew 17 extends, said set screw bein threadedwinto a fan arm 18. Byloosening t e 'screw 1T, the fan blade 6 may be adjusted toany pitchdesired, after which theset screw 17 may be tightened, thereby holdingthe blade in adjusted position. By providing the blade adjustment, it isobvious that the blades may be properly adjusted-in relation to eachother particularly for normal operation of the fan under slow speed ofthe engine.

From the above it will be seen that an adjustable pitch fan is providedfor cooling engines wherein the pitch will vary according to the speedof rotation of the fan, and

that the maximum pitch is obtained during low speed of the engine andfan, at which time a maximum cooling action is desired.

The invention having been set forth what is claimed as new and useful isl. An adjustable pitch cooling fan for internal combustion engines, saidfan comprising a hub having radially disposed chambers, radiallydisposed-fan arms eX-j tending outwardly from said chambers, fan bladescarried by said fan arms, discs on the inner ends of Said fan arms,spirallyarranged ribs carried in the chamber and engaging spirallyarranged grooves in the discs, bushings threaded in the outer ends ofthe `chambers and coiled springs surrounding the fan arms and interposedbetween the discs and the bushings. 4

2. An adjustable pitch cooling fan for internal combustion engines, saidfan com'- prising a hub having radially disposed chambers, radiallydisposed fan arms extending outwardly from said chambers, fan bladescarried by the fan arms, means for adjusting said fan bladescircumferentially on the fan arms, connections between the fan arms andthe hub whereby upon an outward movement of the fan arms, they will bepartially rotated and spring 'means for normally holding said fan armsin inner position upon slow rotation of the fan.

In testimony whereof we hereunto affix our signatures.

CARL LUTHER. HENRY MOELLER.

